The exemplary embodiment relates to the imaging arts. It finds particular application in connection with an air knife stripping system for a fuser assembly and will be described with particular reference thereto.
In typical electrostatographic printing systems, for example, such as copy machines and laser beam printers, a marking engine includes a photoconductive insulating member, such as a photoreceptor belt or drum, which is charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member, which corresponds to the image areas contained within the document. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with a marking material. Generally, the marking material comprises toner particles adhering triboelectrically to carrier granules, which is often referred to simply as toner. The developed image is subsequently transferred to the print medium, such as a sheet of paper. The fusing of the toner image onto paper is generally accomplished by a fuser which applies heat to the toner with a heated fuser roll and application of pressure.
The molten toner has a tendency to stick to the elastomeric surface of the heated fuser roll, especially in the case of rolls with oiled or oil-releasing surfaces. In order to provide a uniform surface treatment by the fuser roll, it is desirable to provide reliable and consistent stripping of the print media sheets from the fusing surface of the roll. Various types of stripping systems have been developed. In an air knife stripping system, for example, jets of air are directed towards the print media to separate the print media from the fuser roll. The jets are emitted from small holes in an elongate surface which extends adjacent the fuser roll. The air jets have a tendency to lower the surface temperature of the fuser roll adjacent the jet, which can result in uneven gloss across the print media. To minimize the flow of air which is used in stripping the print media, and thus the cooling effect, systems have been developed which apply a short burst of air just as the leading edge of the print media reaches the air knife to initiate separation.
If the air knife system develops a leak, such as in the hoses supplying the air, poor stripping can occur, often requiring a service call to diagnose the problem.